Age 749
"Hello?" Bulma asked, sounding tired. She had climbed a long way, after all. The little house near the top of the mountain wasn't exactly what she was expecting.
The Dragon Radar was pointing her towards the small stone building surrounded by what seemed to be the site of some kind of bomb testing. Craters, shattered stone, even occasionally steaming and burned portions of ground littered the area. As she drew close, she began to feel an oppressive sense of something watching her.
"Hello? I uh, I'm Bulma Briefs. From Capsule Corp. I think you have something I'm looking for." she shouted, looking around.
All at once, she found herself in the arms of an old man with a bristly mustache and a determined expression.
"You're in a very dangerous place young woman." the old man said sagely, his eyes darting back and forth, before without warning he kicked off the ground.
Bulma let out a sharp scream as the two of them sailed through the air, landing on top of the stone house.
"P-Put me down!" Bulma demanded, "Look, I'm just here for the Dragon Ball, then I'll leave and never come back, okay?"
"Dragon Ball?"
"It- It should be gold, with red stars inside? I'm collecting them." she explained, "I think you have one."
He narrowed his eyes, "I do. What reason do you have for taking it?"
"If you collect all seven, you can have your wish granted." Bulma said, "At least according to legend."
"Hm." the old man once again looked carefully in every direction. "...He's not here right now. He might be fishing." he muttered, "Fine, act quickly. We don't have much time." He once again jumped with her in his arms, and landed without sound rushing through the door and into the building.
"There, is that it?" he asked, setting her down in front of a pedestal with a pillow on it. On top of the pillow, was what she was looking for.
Her eyes widened and she grinned, "Yes! That's it, absolutely!" she picked it up, putting it in her bag with her own Dragon Ball, before turning towards the old man, "Thank you-"
"Call me Gohan." the old man replied, "Now, we need to go now or Kakarot will-" he stopped, turning his head, "I can sense him."
Bulma went very still as the stone house shook, the force of the primal roar outside tearing through it. "...Be very, very quiet." Gohan growled, "He might get your scent, so be sure to pass as many rivers as you can."
"O-okay."
"Do you have a Capsule Car?"
"Y-yes."
"I'm going to go outside and face him. I want you to leap out one of the windows, and take a car, and get out of here while I'm distracting him. Got it?"
"Okay." she says quietly. Gohan smiles sadly, before rushing for the front entrance. Bulma watched him go, and then hurried for the nearest window. She squeezed herself through the hole in the rock, and made a quick and silent prayer for the safety of the old man against whatever a "Kakarot" was, and drew out a Capsule Car.
Bulma winced at the sound of men screaming and rock shattering as the fight behind seemed to begin in earnest. She made sure to get out of there as fast as she could.
As the hover car sped down the mountainside, she hesitated a moment, looking behind her and taking in the fight.
Gohan and Kakarot darted from place to place, their movements seemingly almost ghost-like in her eyes. In a second, the two traded dozens of blows. Kakarot was a child- or maybe a young teenager, but she supposed that wasn't any proof against him being weak. After all, his opponent was a man clearly well into his seventies, maybe older. The two of them sounded almost like a thunderstorm, the clash of their fists sounding like thunder, the air moving with their incredibly fast movements sounding like howling winds.
"Today will be your last day alive Grandpa!"
"Not quite yet Kakarot!"
She hurried away, and never looked back.
"Who was that man, Grandpa?" Kakarot asked, once their daily duel had finished and they ate their evening meal. The relationship the two had was a truly bizarre one. Gohan had found Kakarot wandering the woods when he was only three years old. The child attacked Gohan, recognizing him as a member of the species he was here to wipe out, only to be easily and thoroughly defeated.
But Gohan was a man of mercy. And someone who was determined. The old man had taken the child in, fed him, and went to sleep- only to awaken in the dead of night as Kakarot attempted to strangle him. From there, over ten years of struggles, the two had hashed out a kind of livable compromise between them both.
The two would duel, once a day, and spend the rest of their time training and preparing. They ate together, slept without harming each other, and each day the two of them trained for their duel at noon. In each fight, Kakarot would do his damndest to kill Gohan, and Gohan would do everything he could to knock Kakarot out. After the first two times the Oozaru had wreaked havoc, he also made sure to keep their bedtime very early, something Kakarot agreed to once Gohan explained that getting lots and lots of sleep would help him to become a great warrior.
But most importantly, Kakarot would not venture out into the rest of the world until he defeated Gohan.
"Man- I suppose you wouldn't know." Gohan said, "That wasn't a man, that was a woman."
"No, that was a man, a human. I smelled him. He's human."
"Err, well, there's two kinds of humans. Men, and women. The two of us are men-"
"I'm not a human!"
"-er, that is to say, we're male." Now, grandpa Gohan himself hadn't had much interaction with women in his long life.
As a child, he had been taught under Master Roshi, so he knew of women, he knew what they looked like, and what, in Roshi's narrow, incorrect, and perverted opinion, women were for.
In his own life, Gohan hadn't spent enough time interacting with civilization beyond a few small towns to know otherwise.